What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Screws are a kind of fasteners commonly used in machinery, but most of the screws commonly used in the market are standard parts. The screws themselves are ordinary and have no function of preventing loosening and protecting the matrix. Therefore, in order to prevent the screws from loosening during use , Usually it is necessary to configure additional elastic washers, flat washers, etc. that are suitable for screws, and these elastic washers and flat washers are mostly metal products. During use, it is easy to wear with the body base and damage the protection of the sheet metal base. After long-term use, metal washers are easy to rust, which affects the tightening effect and appearance of screws. In addition, the use of metal washers not only increases the weight and cost, but also the assembly process is complicated and cumbersome, and the anti-loosening and anti-wear effects are not ideal. .
When using a rivet nut, drill a hole corresponding to the outer diameter of the rivet nut on the thin wall, then place the rivet nut on the bolt of the special rivet gun, push the handle to screw in the rivet nut, and put it into the drilled hole. In the workpiece, squeeze the handle, the rivet nut expands, and the deformed skirt bulges and deforms. At this time, the workpiece is tightened. After riveting, the handle is pulled out, the bolt is released from the rivet nut, and the corresponding screw is screwed into the rivet nut threaded hole. , forming a tight riveted body.
The main categories of screws include ordinary screws, machine screws, self-tapping screws and expansion screws. Cap screws used to be limited to full-thread fasteners. Hex cap screw and Hex bolt Hex bolt As the name suggests, it is a male threaded fastener with a hexagonal head, designed to be turned with a wrench. According to the ASME B18.2.1 standard, the head height and shank length tolerance of the hexagon head screw (Hex cap screw) is smaller than that of the general hex bolt (Hex bolt), so the ASME B18.2.1 hexagon screw is suitable for installation in all hexagon bolts that can be used. places, also including places where the large hex bolts are too large to be used. Socket cap screw (also known as socket head screw or) is a screw with a hexagonal inner hole on the head, which can be tightened or loosened only after a hexagonal ruler (hex key, Allen wrench or Allen key) is inserted into the inner hole. The most commonly used hexagon socket head screws are cylindrical head screws with a head diameter of about 1.5 times the main diameter of the thread (1960 series). Countersunk head cap screw. The counterbore design allows the screw head to rotate without being exposed on the surface of the fixed object, so it is mostly used in places where the surface is small and traditional wrenches are inconvenient to use. Machine screw is generally a screw (4#~12#) with a diameter less than ¼ inches, usually full teeth and rotated by a screwdriver, such as slotted, cross or hexagon socket. Wood screws, machine screws; but can be divided into many categories according to different uses; machine screws can be divided into longitudinal tightening screws and horizontal expansion screws; according to the thread can also be divided into: A: Triangular thread (60 degrees ) : combined/locked/expanded B: triangular thread for pipe (55 degrees): combined/locked 3) C: trapezoidal thread (30 or 29 degrees): power transmission D: square thread (90 degrees): power transmission stainless steel screw Stainless Steel Anti-Drop ScrewsStainless Steel Anti-Drop Screws Machine (Treadmill) Screws And Shafts For Motorcycle Or Bicycle Needle Car Screws, Axes Screws And Shafts For Sewing Macing Socket Set Screws Stainless Steel Wide Thread ScrewsStainless Steel Coarse Thread Screws Stainless Steel High-Low Thread Screws Stainless Steel Machine Screws Stainless Steel Self Drilling Screws Stainless Steel Self Tapping Screws Stainless Steel Self Tapping Screws Stainless Steel Thread Cutting Screws Stainless Steel Triangle Stainless Steel Tri-Lobular Thread Screws Model Description P refers to the head type is PAN head; A refers to the pointed tail teeth, B refers to the flat tail teeth, namely PA round head pointed steel teeth, PB round head flat mouth steel teeth. Self-tapping type: ◆Round head self-tapping screw PA ◆Round head flat tail self-tapping screw PB ◆Round head cutting tail self-tapping screw PT ◆Round head belt self-tapping screw PWA ◆Round head belt and flat tail self-tapping PWB ◆Round head belt Jiecut tail self-tapping PWT ◆Countersunk head self-tapping screw KA ◆Countersunk head flat tail self-tapping screw KB ◆Countersunk head cut-tail self-tapping screw KT ◆Semi-countersunk head self-tapping screw OA ◆Big head self-tapping screw BA ◆Big head flat tail self-tapping screw BB ◆Large flat head self-tapping screw TA ◆Large flat head flat tail self-tapping screw TB ◆Large flat head cutting tail self-tapping screw TT ◆Thin head self-tapping screw CA ◆Thin head flat tail self-tapping screw CB ◆Cup head hexagon socket self-tapping HA ◆Drywall/Wallboard/Fiber Nails Machine Wires: ◆Round Head Machine Screw PM ◆Round Head Machine Screw PWM ◆Large Flat Head Machine Screw TM ◆Countersunk Head Machine Screw KM ◆Half Countersunk Head machine screw OM ◆Large head machine screw BM ◆Thin head machine screw CM ◆Cup head machine screw HM
As the preferred embodiment of the above-mentioned embodiment, the motor 41 is provided with a thruster 46 that moves the cutting wheel 42 toward the conveying device 3. When the screw needs to be slotted, the thruster 46 generates a thrust toward the screw, and the motor 41 generates a thrust in the direction of the screw. Under the action, the groove is moved along the track 47 toward the screw. The other end of the motor 41 is provided with a bearing 45, and the output end of the motor is provided with a special-shaped wheel 44. The special-shaped wheel 44 is geared to the bearing 45. The wheel 42 is close to or away from the conveying device 3. When the grooving is completed, the special-shaped wheel 44 rotates and drives the bearing 45 to generate the opposite force from the above-mentioned thrust, so that the motor 41 moves back to the initial position along the track 48.
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